Project Summary Voice disorders are debilitating and can lead to significant socioemotional consequences, loss of income, and long-term disability. Among otolaryngology evaluations for dysphonia, iatrogenic etiologies (most consequent from thyroidectomy or anterior cervical disc fusion surgery) account for an estimated 50% new cases of unilat- eral vocal fold paralysis (UVFP) annually. The symptomatic burden of UVFP on patients is significant with an estimated 100% of identified cases experiencing dysphonia, 60% dyspnea, and 75% dysphagia, which, in severe cases, can lead to aspiration pneumonia and death. Treatment requires medialization of the paralyzed vocal fold to reestablish glottal closure. Several modalities exist to achieve closure, including in- jection augmentation. However, injection augmentation is effective at only temporarily alleviating symptoms, and surgical intervention is ultimately necessary in more than half of patients diagnosed with UVFP (Francis et al. 2016). Permanent framework surgery remains the gold standard for patients that are beyond the period of spontaneous recovery (usually 6-12 months). The current proposal focuses specifically on framework surgery, of which type I laryngoplasty is most common. Indications for this procedure extend well beyond UVFP to include a growing population of patients with glottal insufficiency from other causes (e.g., presbyphonia). Although these patients benefit from type I laryngoplasty, surgical techniques and revision rates vary widely and are largely volume-dependent and experiential. Unfortunately, such variation produces inconsistent and undesirable clinical outcomes. Thus, there exists a significant need for a clinical tool to assist surgeons with pre-operative planning and to improve patient outcomes. To address this need, we have assembled a multidisciplinary group of engineers, scientists, and surgeons to work towards a patient-specific surgical planning tool for type I laryngoplasty (PhonoSim). It is envisioned that a tool that incorporates the surgical implant, and captures the individual-specific features of the patient?s laryngeal anatomy can be used in surgical planning to optimize the shape, size, and position of implants used in type I laryngoplasty to improve clinical outcomes. This proposal leverages current advances in microimaging, computational modeling, and high-performance computing of biological systems to support the development and validation of a surgical planning tool for type I laryngoplasty. Our preliminary work has focused on: 1) development of a versatile computational approach for the simulation of 3D fluid-structure interactions involving large deformations, and 2) validation of computational models of phonation and for the first time the modeling of subject-specific vibratory characteristics. The goal of this proposal is to empirically test the modeling and validation approaches developed in our preliminary work to produce a clinical tool to be used in future human studies. The deliverable upon grant completion will be a clinical tool to be rigorously tested in future phase I/II human trials.